/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.shardingsphere.proxy.frontend.postgresql.command.query.binary.bind;

import lombok.RequiredArgsConstructor;
import org.apache.shardingsphere.db.protocol.packet.DatabasePacket;
import org.apache.shardingsphere.db.protocol.postgresql.packet.command.query.PostgreSQLColumnDescription;
import org.apache.shardingsphere.db.protocol.postgresql.packet.command.query.PostgreSQLRowDescriptionPacket;
import org.apache.shardingsphere.db.protocol.postgresql.packet.command.query.binary.PostgreSQLBinaryStatementRegistry;
import org.apache.shardingsphere.db.protocol.postgresql.packet.command.query.binary.bind.PostgreSQLBindCompletePacket;
import org.apache.shardingsphere.db.protocol.postgresql.packet.command.query.binary.bind.PostgreSQLComBindPacket;
import org.apache.shardingsphere.proxy.backend.communication.jdbc.connection.BackendConnection;
import org.apache.shardingsphere.proxy.backend.response.header.ResponseHeader;
import org.apache.shardingsphere.proxy.backend.response.header.query.QueryResponseHeader;
import org.apache.shardingsphere.proxy.backend.response.header.query.impl.QueryHeader;
import org.apache.shardingsphere.proxy.backend.response.header.update.UpdateResponseHeader;
import org.apache.shardingsphere.proxy.frontend.command.executor.CommandExecutor;
import org.apache.shardingsphere.db.protocol.postgresql.packet.command.query.binary.PostgreSQLBinaryStatement;
import org.apache.shardingsphere.proxy.frontend.postgresql.command.PostgreSQLConnectionContext;
import org.apache.shardingsphere.proxy.frontend.postgresql.command.query.binary.PostgreSQLPortal;

import java.sql.SQLException;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;

/**
 * Command bind executor for PostgreSQL.
 */
@RequiredArgsConstructor
public final class PostgreSQLComBindExecutor implements CommandExecutor {
    
    private final PostgreSQLConnectionContext connectionContext;
    
    private final PostgreSQLComBindPacket packet;
    
    private final BackendConnection backendConnection;
    
    @Override
    public Collection<DatabasePacket<?>> execute() throws SQLException {
        PostgreSQLBinaryStatement binaryStatement = PostgreSQLBinaryStatementRegistry.getInstance().get(backendConnection.getConnectionId(), packet.getStatementId());
        PostgreSQLPortal portal = connectionContext.createPortal(packet.getPortal(), binaryStatement, packet.getParameters(), packet.getResultFormats(), backendConnection);
        List<DatabasePacket<?>> result = new LinkedList<>();
        result.add(new PostgreSQLBindCompletePacket());
        ResponseHeader responseHeader = portal.execute();
        if (responseHeader instanceof QueryResponseHeader) {
            connectionContext.getDescribeExecutor().ifPresent(describeExecutor -> describeExecutor.setRowDescriptionPacket(createRowDescriptionPacket((QueryResponseHeader) responseHeader)));
        }
        if (responseHeader instanceof UpdateResponseHeader) {
            connectionContext.setUpdateCount(((UpdateResponseHeader) responseHeader).getUpdateCount());
        }
        return result;
    }
    
    private PostgreSQLRowDescriptionPacket createRowDescriptionPacket(final QueryResponseHeader queryResponseHeader) {
        Collection<PostgreSQLColumnDescription> columnDescriptions = createColumnDescriptions(queryResponseHeader);
        return new PostgreSQLRowDescriptionPacket(columnDescriptions.size(), columnDescriptions);
    }
    
    private Collection<PostgreSQLColumnDescription> createColumnDescriptions(final QueryResponseHeader queryResponseHeader) {
        Collection<PostgreSQLColumnDescription> result = new LinkedList<>();
        int columnIndex = 0;
        for (QueryHeader each : queryResponseHeader.getQueryHeaders()) {
            result.add(new PostgreSQLColumnDescription(each.getColumnName(), ++columnIndex, each.getColumnType(), each.getColumnLength(), each.getColumnTypeName()));
        }
        return result;
    }
}
